The Russians are on the move in the Middle East. "Fuse K6!" cracks the order over the intercom of a giant jet bomber.

Squadron Leader John Falkner and his crew whip into action. They arm their awesome cargo, a giant nuclear weapon capable of destroying 40,000 square miles.

Then comes the order to defuse the bomb. The Russians are withdrawing. The proper procedure is followed - several times - but two warning red lights continue to blink. K6 will not defuse, their fuel is low and the bomb is set to automatically detonate at an altitude of 5,000 feet.

David Beaty's Cold War thriller is a classic of its genre.